1. Field of the invention
The present invention is related generally to a memory card, more particularly to a memory card which improves the reliability of data such as image data formed in a standardized data format and yet maintains the compatibility of the data.
2. Description of the prior art
The image data used in the Internet and a digital camera has a standardized format and is handled by an information processing device such as a personal computer. The image data comprises a large amount of pixel data and a small amount of control data for specifying, for example, color information, display size, and a compression scheme. A small error of a few bits made in the large pixel data portion affects only a few pixels among a vast number of pixels in a whole image and will cause only a negligible problem. However, even a one-bit error in the control data portion affects the entire image and, in some cases, may cause the image to disappear completely.
From the foregoing one can expect that data correction for only the control data portion will effectively improve data reliability when image data is stored in a memory card. A problem, however, is that adding an error correction code to the image data causes its data format to deviate from the standardized format and makes the image data incompatible. Therefore, the error correction code must be stored in a memory space separate from the image data memory space. However, since the size of the image data varies, the spatial relation between the memory space for storing the error correction codes and the main memory space for storing the image data cannot be fixed.